Apparatus for smoothing and polishing stone



W. MAcGREGOB.

APPARATUS FOR SMOOTI'IING AND POLISHING STONE.

APPLICATION FILED FEB. 9. I918- wl'mzssss Patented J an. 6 1920.

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- APPARATUS FOR SMOOTHING AND POLISHING STONE. v

. APPLICATION FILED rssi a. ma. 1,327,440, Patented Jan. 6, 1920.

3 SHEETS-SEEN 2-- 3 SHEETS-SHEET 3- w MAcGREGOR. APPARATUS FOR smoonuwe AND POLISHING STONE. APPLICATION FILED FEB. 9, IQIB. 1,327,440, Patented Jan. 6, 1920.

an n? 9 IEIIII $53k [I UNITED T E PATENT O E- WILLIAM MACGREGOR, OF NlIAGARA FALLS,

' DUM COMPANY, OF NIAGARA FALLS, N

VAN IA.

Specification of Letters ratent.

NEW YORK, ASSIGNOR ro THE cAItBoIwN- nw YORK, A conrpnA'rIoN or PENNSYL- APPARATUS non sivroorr-mve AND POLISHING s'romr.

Patented Jan. 6, 1920.

I Application fi1ed February 9, 1918. Serial No. 216,209.

To all whom it concern:

Be it known that 1, WILLIAM MACGREGOR,

' a. subject'of the Kin of Great Britain, residing at Niagara Fal s, in the county of Niagara and State of New York, have invented. a new and useful Improvement in Apparatus for Smoothing and Polishing Stone, of which the followin is a full, c1ear,'and exact description, re accompanying drawings, forming part of this specification in which- Figure l is a plan view of a machine embodymg my invention.

Fig. 2 is a side'elevation of the same.

Fig. 3 is a section on the line III-J11 of Fi 2. 7 I %ig. 4 is an end elevation, and

Fig. 5 is a sectional view showing a spe-' cial form of grinding head.

My invention relates to machines for smoothing and polishing marble, concrete and other kinds of natural and artificial stone, and is particularly useful in the rubbing and smoothing of blocks and slabs of marble after they have been sawed from quarried blocks, for the purpose of smoothing the sawed surfaces and giving them a uniforni plane surface for further treatment in honing and polishing. This operappripheral feet per minute.

tion is technically known as rubbing. v The re ular practice heretofore has been to place t e blocks orslabs on a rubbing bed conslsting of a large flat' cii'cular table of cast iron revolving at a speed of about 2000 om 6 to 18 feet in diameter. The slabs are laid on the bed and are held in fixed'position thereon. A supply of sand and water v is fed to the center of the bed and this sand works toward the peri hery, cutting the marble to a smooth sur ace as it is drawn thereunder. A

The. process is a slow and ex ensive one and requires a constant supply. 0' new sharp sand. My invention is designed to provide smoothing and polishing apparatus in which the'work can bedone much more rapidly than with the old process,-.which will give a smoother and better. finish, and by which the output maybe greatly increased. My in- .vention alsoimproves the general workingconditions, making them quicker and more healthful.

rence being had to the Such beds vary Referring to the accompanying drawings in which I have shown a preferred embodi ment of my invention, the numeral 2 designates a reciprocating table or carrier for the piece A of marble or other material to be smoothed. This table or carrier is mounted in V-grooves 3 on a bed 4, and is designed to travel backward and forward in the manner of the work carrier or table of a-metal planing machine. 5 designates a rack and pinion mechanism for reciprocating the table andwhich is driven from the shaft 6 in any manner well known to the operation shaft 6 may be driven by means of the pulleys 7. The reversal of'the table is also ef fectedin any usual manner. v

Side posts 10 are rigidly connected to the 7 bed t and carry a cross-head or carriage 12 above the table 2, this cross-head or carrlage being mounted for vertical movement 'in suitable guides 13. 1 The vertical moveof planing machines, this driving means forming no part of my invention. The

ment of the head is effected by means of the screws 14 actuated manually by a suitable hand wheel or lever applied to the shaft 15-, which is connected by gears '16 with a crossshaft 17 connected by bevel gears 18 with.

each of said screws; or any well known autoing pulleys 9. On the lower end of the shaft 19 is a head or chuck 24 in which is secured a grinding wheel 25, which is preferably vertical .shaft which is composediof'carborundu'm blocks or sections suitably secured in the head or chuck and which is of sufficient diameter to span the full working width of the table 2; or at least of suflicient diameter to span the entire width of the pieces .of stone to be rubbed.

' The operat1on will be readily understood. The reciprocating carriage carries the stone underneath the grlnding Wheel, which is rotated atvthe desired rate of speed, prefer ably from 2000 to 5000 peripheral feet per minute, the cross-head being fed down as may be required.

The use of this machine efiects a great saving in time over'theold method owing to the high rate of speed at which the grinding wheel may be driven; and as the cutting action of said wheel is limited only by the amount of power that can be supplied to it, the amount of marble cut off in a given time will greatly exceed that with the old machine heretofore used. The grinding wheel covers the entire slab or block of stone during each traverse and leaves a finish which is very much smoother than can be obtained with the old form of rubbing beds. By using a grinding wheel of carborundum, the output results are greatlyincreased, owing to the very superior cutting power of this material as compared with that of sand. The general working conditions are also rendered more healthful.

A further advantage of my invention 1s the obtaining of a surface of superior smoothness without ridges or lines, such as are left by the sand in the old form of machines.

I am aware that it has been proposed heretofore to finish marble by using a plurality of grinding heads which are arranged together to cover the whole surface of the marble slab as it was passed under such heads- This method, however, has not proven successful because the heads follow' the original windings in the slab and rise and fall with the hard and soft spots therein, giving an irregular finish. This is entirely overcome by using a single solid wheel covering the whole widthof the slab.

In Fig. 5 I have shown a form of grinding wheel or head, which is of special advantage where successive smoothing and polishing operations are employed to give a successively higher degree of smoothness to the stone.

In this figure of the drawings, 26 designates a hollow sleeve shaft which. is journaled in the cross-head 12 which may be similar to the cross-head 12 before described, and which is shown as being driven by the gears 22 and 23 in the same manner as the shaft 19 before described. This sleeve shaft has secured to its lower end a main head or chuck 27 in which is secured an annular grinding ring 28. This grinding ring may, for instance, be composed of carborundum blocks of #40 grit, such as would be used for roughing cut.

29 designates anothengrinding ring arranged concentrically within the rin 28 and carried-by a head or chuck 30 whic is secured to the lower end of the shaft 31, which is keyed to the hollow shaft 26 to rotate therewith, while capable of vertical movement therein. The ring' 29 may be composed of carborundurn of a much finer grit,

slide vertically through the gear 22 on the driving key 34.

Inl using this form of head, in the first operation, the coarse grinding ring 28 is lowered by lowering the cross-head l2 into the position for the roughing cut, the'fine grinding ring 29 being at this time raised sufficiently within the head or chuck 27 so that its grinding surface will not contact with the work. After the roughing cut the fine grinding ring 29 is lowered to a position where its grinding surface is below the level of the grinding surface of the ring 28.

After these first two cuts, the grinding heads can be removed and another head substituted having suitable means for efiecting the later operations of honing and shining o r glossing. For this purpose the outer rlng may be composed vof carborundum blocks of FF grit, and the final shining or glossing ring may consist of a felt mop. In connection with this mop oxalic acid crystals may be used, or a mixture of oxalic acid and putty powder; or any other polishing materials of known or suitable character.

I do notdesire to limit myself to the particular construction-and arrangement of the parts which I have herein shown and described, since, obviously, many changes can be made therein within the spirit and scope of the appended claims, thus any suitable driving means may be employed for rotating the grinding wheel; the grinding parts of the latter may be of any suitable material; various means may be employed for moving one of the grinding rings relatively to the other where a combined form of head is employed; and a greater number of concentric grinding rings of different de- ,grees of cutting or smoothing action may be used.

I claim:

1. A grinding or polishing head having i '2. A grinding or polishing head, compris ing a plurality of concentric grinding or pol shmg rings concentrically mounted on a single vertical guiding shaft, and means for moving said rings verticallyrelatively to each other; substantially as described.

aee'a eee 3.- In a machine of the class described, a grinding head having a plurality of concentric grinding or polishing elements, means for raising and lowering said elements simultaneously, and means whereby at least one of said elements can be raised or lowered with respect to another element; substantially as described.

4. In a machine of the character described, a hollow shaft, an annular grinding or polishing element carried thereby, another grinding or polishing element arranged concentrically within. the first named element,"a rod or shaft connected thereto and secured to the first named shatt to rotate therewith, 15

and means for raisin and lowering the second named shaft to t ereby adjust the posi tion of the second named grinding element with respect to the first named grinding element; substantially as described.

In testimony whereof, I have hereunto set my hand.

W LLIAM MACGREGQ'R. 

